package k8s

import (
	"context"
	"errors"
	"fmt"
	"strings"
	"time"

	"scm.bstein.dev/bstein/soteria/internal/api"
	"scm.bstein.dev/bstein/soteria/internal/config"

	batchv1 "k8s.io/api/batch/v1"
	corev1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
)

const (
	labelAppName   = "app.kubernetes.io/name"
	labelComponent = "app.kubernetes.io/component"
	labelAction    = "soteria.bstein.dev/action"
	labelPVC       = "soteria.bstein.dev/pvc"
)

func (c *Client) CreateBackupJob(ctx context.Context, cfg *config.Config, req api.BackupRequest) (string, string, error) {
	if req.Namespace == "" {
		return "", "", errors.New("namespace is required")
	}
	if req.PVC == "" {
		return "", "", errors.New("pvc is required")
	}
	if req.Snapshot {
		return "", "", errors.New("snapshot support is not implemented yet")
	}

	jobName := jobName("backup", req.PVC)
	secretName := fmt.Sprintf("soteria-%s-restic", jobName)

	if req.DryRun {
		return jobName, secretName, nil
	}

	secret, err := c.copySecret(ctx, cfg.SecretNamespace, cfg.ResticSecretName, req.Namespace, secretName, map[string]string{
		labelAppName:   "soteria",
		labelComponent: "restic",
		labelAction:    "backup",
		labelPVC:       req.PVC,
	})
	if err != nil {
		return "", "", err
	}

	job := buildBackupJob(cfg, req, jobName, secretName)
	created, err := c.Clientset.BatchV1().Jobs(req.Namespace).Create(ctx, job, metav1.CreateOptions{})
	if err != nil {
		_ = c.Clientset.CoreV1().Secrets(req.Namespace).Delete(ctx, secretName, metav1.DeleteOptions{})
		return "", "", err
	}

	if err := c.bindSecretToJob(ctx, req.Namespace, secret.Name, created); err != nil {
		return jobName, secretName, err
	}

	return jobName, secretName, nil
}

func (c *Client) CreateRestoreJob(ctx context.Context, cfg *config.Config, req api.RestoreTestRequest) (string, string, error) {
	if req.Namespace == "" {
		return "", "", errors.New("namespace is required")
	}

	snapshot := req.Snapshot
	if snapshot == "" {
		snapshot = "latest"
	}

	jobName := jobName("restore", snapshot)
	secretName := fmt.Sprintf("soteria-%s-restic", jobName)

	if req.DryRun {
		return jobName, secretName, nil
	}

	secret, err := c.copySecret(ctx, cfg.SecretNamespace, cfg.ResticSecretName, req.Namespace, secretName, map[string]string{
		labelAppName:   "soteria",
		labelComponent: "restic",
		labelAction:    "restore",
	})
	if err != nil {
		return "", "", err
	}

	job := buildRestoreJob(cfg, req, jobName, secretName, snapshot)
	created, err := c.Clientset.BatchV1().Jobs(req.Namespace).Create(ctx, job, metav1.CreateOptions{})
	if err != nil {
		_ = c.Clientset.CoreV1().Secrets(req.Namespace).Delete(ctx, secretName, metav1.DeleteOptions{})
		return "", "", err
	}

	if err := c.bindSecretToJob(ctx, req.Namespace, secret.Name, created); err != nil {
		return jobName, secretName, err
	}

	return jobName, secretName, nil
}

func buildBackupJob(cfg *config.Config, req api.BackupRequest, jobName, secretName string) *batchv1.Job {
	labels := map[string]string{
		labelAppName:   "soteria",
		labelComponent: "backup",
		labelAction:    "backup",
		labelPVC:       req.PVC,
	}

	command := backupCommand(cfg, req)

	pod := corev1.PodSpec{
		RestartPolicy: corev1.RestartPolicyNever,
		Containers: []corev1.Container{
			{
				Name:            "restic",
				Image:           cfg.ResticImage,
				ImagePullPolicy: corev1.PullIfNotPresent,
				Command:         []string{"/bin/sh", "-c"},
				Args:            []string{command},
				Env:             resticEnv(cfg, secretName),
				VolumeMounts: []corev1.VolumeMount{
					{Name: "data", MountPath: "/data", ReadOnly: true},
					{Name: "cache", MountPath: "/cache"},
				},
			},
		},
		Volumes: []corev1.Volume{
			{
				Name: "data",
				VolumeSource: corev1.VolumeSource{
					PersistentVolumeClaim: &corev1.PersistentVolumeClaimVolumeSource{
						ClaimName: req.PVC,
						ReadOnly:  true,
					},
				},
			},
			{
				Name: "cache",
				VolumeSource: corev1.VolumeSource{
					EmptyDir: &corev1.EmptyDirVolumeSource{},
				},
			},
		},
	}

	if cfg.WorkerServiceAccount != "" {
		pod.ServiceAccountName = cfg.WorkerServiceAccount
	}

	return &batchv1.Job{
		ObjectMeta: metav1.ObjectMeta{
			Name:      jobName,
			Namespace: req.Namespace,
			Labels:    labels,
		},
		Spec: batchv1.JobSpec{
			BackoffLimit:            int32Ptr(0),
			TTLSecondsAfterFinished: int32Ptr(cfg.JobTTLSeconds),
			Template: corev1.PodTemplateSpec{
				ObjectMeta: metav1.ObjectMeta{Labels: labels},
				Spec:       pod,
			},
		},
	}
}

func buildRestoreJob(cfg *config.Config, req api.RestoreTestRequest, jobName, secretName, snapshot string) *batchv1.Job {
	labels := map[string]string{
		labelAppName:   "soteria",
		labelComponent: "restore",
		labelAction:    "restore",
	}

	command := restoreCommand(snapshot)

	pod := corev1.PodSpec{
		RestartPolicy: corev1.RestartPolicyNever,
		Containers: []corev1.Container{
			{
				Name:            "restic",
				Image:           cfg.ResticImage,
				ImagePullPolicy: corev1.PullIfNotPresent,
				Command:         []string{"/bin/sh", "-c"},
				Args:            []string{command},
				Env:             resticEnv(cfg, secretName),
				VolumeMounts: []corev1.VolumeMount{
					{Name: "restore", MountPath: "/restore"},
					{Name: "cache", MountPath: "/cache"},
				},
			},
		},
		Volumes: []corev1.Volume{
			{
				Name: "restore",
				VolumeSource: corev1.VolumeSource{
					EmptyDir: &corev1.EmptyDirVolumeSource{},
				},
			},
			{
				Name: "cache",
				VolumeSource: corev1.VolumeSource{EmptyDir: &corev1.EmptyDirVolumeSource{}},
			},
		},
	}

	if req.TargetPVC != "" {
		pod.Volumes[0] = corev1.Volume{
			Name: "restore",
			VolumeSource: corev1.VolumeSource{
				PersistentVolumeClaim: &corev1.PersistentVolumeClaimVolumeSource{
					ClaimName: req.TargetPVC,
					ReadOnly:  false,
				},
			},
		}
		labels[labelPVC] = req.TargetPVC
	}

	if cfg.WorkerServiceAccount != "" {
		pod.ServiceAccountName = cfg.WorkerServiceAccount
	}

	return &batchv1.Job{
		ObjectMeta: metav1.ObjectMeta{
			Name:      jobName,
			Namespace: req.Namespace,
			Labels:    labels,
		},
		Spec: batchv1.JobSpec{
			BackoffLimit:            int32Ptr(0),
			TTLSecondsAfterFinished: int32Ptr(cfg.JobTTLSeconds),
			Template: corev1.PodTemplateSpec{
				ObjectMeta: metav1.ObjectMeta{Labels: labels},
				Spec:       pod,
			},
		},
	}
}

func backupCommand(cfg *config.Config, req api.BackupRequest) string {
	args := []string{"restic", "backup", "/data", "--tag", "soteria", "--tag", fmt.Sprintf("pvc=%s", req.PVC)}
	for _, tag := range req.Tags {
		tag = strings.TrimSpace(tag)
		if tag == "" {
			continue
		}
		args = append(args, "--tag", tag)
	}
	args = append(args, cfg.ResticBackupArgs...)

	cmd := strings.Join(args, " ")
	if len(cfg.ResticForgetArgs) > 0 {
		forget := strings.Join(append([]string{"restic", "forget"}, cfg.ResticForgetArgs...), " ")
		cmd = fmt.Sprintf("%s && %s", cmd, forget)
	}

	return "set -euo pipefail; " + cmd
}

func restoreCommand(snapshot string) string {
	return fmt.Sprintf("set -euo pipefail; restic restore %s --target /restore", snapshot)
}

func resticEnv(cfg *config.Config, secretName string) []corev1.EnvVar {
	env := []corev1.EnvVar{
		{Name: "RESTIC_REPOSITORY", Value: cfg.ResticRepository},
		{Name: "RESTIC_CACHE_DIR", Value: "/cache"},
		{
			Name: "AWS_ACCESS_KEY_ID",
			ValueFrom: &corev1.EnvVarSource{SecretKeyRef: &corev1.SecretKeySelector{LocalObjectReference: corev1.LocalObjectReference{Name: secretName}, Key: "AWS_ACCESS_KEY_ID"}},
		},
		{
			Name: "AWS_SECRET_ACCESS_KEY",
			ValueFrom: &corev1.EnvVarSource{SecretKeyRef: &corev1.SecretKeySelector{LocalObjectReference: corev1.LocalObjectReference{Name: secretName}, Key: "AWS_SECRET_ACCESS_KEY"}},
		},
		{
			Name: "RESTIC_PASSWORD",
			ValueFrom: &corev1.EnvVarSource{SecretKeyRef: &corev1.SecretKeySelector{LocalObjectReference: corev1.LocalObjectReference{Name: secretName}, Key: "RESTIC_PASSWORD"}},
		},
	}

	if cfg.S3Endpoint != "" {
		env = append(env, corev1.EnvVar{Name: "RESTIC_S3_ENDPOINT", Value: cfg.S3Endpoint})
		env = append(env, corev1.EnvVar{Name: "AWS_ENDPOINT", Value: cfg.S3Endpoint})
	}
	if cfg.S3Region != "" {
		env = append(env, corev1.EnvVar{Name: "AWS_REGION", Value: cfg.S3Region})
		env = append(env, corev1.EnvVar{Name: "AWS_DEFAULT_REGION", Value: cfg.S3Region})
	}

	return env
}

func (c *Client) copySecret(ctx context.Context, srcNS, srcName, dstNS, dstName string, labels map[string]string) (*corev1.Secret, error) {
	secret, err := c.Clientset.CoreV1().Secrets(srcNS).Get(ctx, srcName, metav1.GetOptions{})
	if err != nil {
		return nil, fmt.Errorf("read secret %s/%s: %w", srcNS, srcName, err)
	}

	copy := &corev1.Secret{
		ObjectMeta: metav1.ObjectMeta{
			Name:      dstName,
			Namespace: dstNS,
			Labels:    labels,
		},
		Type: secret.Type,
		Data: secret.Data,
	}

	created, err := c.Clientset.CoreV1().Secrets(dstNS).Create(ctx, copy, metav1.CreateOptions{})
	if err != nil {
		return nil, fmt.Errorf("create secret %s/%s: %w", dstNS, dstName, err)
	}

	return created, nil
}

func (c *Client) bindSecretToJob(ctx context.Context, namespace, secretName string, job *batchv1.Job) error {
	secret, err := c.Clientset.CoreV1().Secrets(namespace).Get(ctx, secretName, metav1.GetOptions{})
	if err != nil {
		return err
	}

	controller := true
	secret.OwnerReferences = append(secret.OwnerReferences, metav1.OwnerReference{
		APIVersion: "batch/v1",
		Kind:       "Job",
		Name:       job.Name,
		UID:        job.UID,
		Controller: &controller,
	})

	_, err = c.Clientset.CoreV1().Secrets(namespace).Update(ctx, secret, metav1.UpdateOptions{})
	return err
}

func jobName(action, suffix string) string {
	base := sanitizeName(fmt.Sprintf("soteria-%s-%s", action, suffix))
	timestamp := time.Now().UTC().Format("20060102-150405")
	name := fmt.Sprintf("%s-%s", base, timestamp)
	if len(name) <= 63 {
		return name
	}
	trimmed := base
	maxBase := 63 - len(timestamp) - 1
	if maxBase < 1 {
		maxBase = 1
	}
	if len(trimmed) > maxBase {
		trimmed = trimmed[:maxBase]
	}
	return fmt.Sprintf("%s-%s", trimmed, timestamp)
}

func sanitizeName(value string) string {
	value = strings.ToLower(value)
	value = strings.ReplaceAll(value, "_", "-")
	value = strings.ReplaceAll(value, ".", "-")
	value = strings.ReplaceAll(value, " ", "-")
	value = strings.Trim(value, "-")
	return value
}

func int32Ptr(val int32) *int32 {
	return &val
}